diff options
| -rw-r--r-- | courgette/difference_estimator.cc | 22 |
1 files changed, 13 insertions, 9 deletions
diff --git a/courgette/difference_estimator.cc b/courgette/difference_estimator.cc index f2f09e1..82c23ee 100644 --- a/courgette/difference_estimator.cc +++ b/courgette/difference_estimator.cc @@ -41,6 +41,8 @@ class DifferenceEstimator::Base { explicit Base(const Region& region) : region_(region) { } void Init() { + if (region_.length() < kTupleSize) + return; const uint8* start = region_.start(); const uint8* end = region_.end() - (kTupleSize - 1); for (const uint8* p = start; p < end; ++p) { @@ -96,16 +98,18 @@ DifferenceEstimator::Subject* DifferenceEstimator::MakeSubject( size_t DifferenceEstimator::Measure(Base* base, Subject* subject) { size_t mismatches = 0; - const uint8* start = subject->region().start(); - const uint8* end = subject->region().end() - (kTupleSize - 1); - - const uint8* p = start; - while (p < end) { - size_t hash = HashTuple(p); - if (base->hashes_.find(hash) == base->hashes_.end()) { - ++mismatches; + if (subject->region().length() >= kTupleSize) { + const uint8* start = subject->region().start(); + const uint8* end = subject->region().end() - (kTupleSize - 1); + + const uint8* p = start; + while (p < end) { + size_t hash = HashTuple(p); + if (base->hashes_.find(hash) == base->hashes_.end()) { + ++mismatches; + } + p += 1; } - p += 1; } if (mismatches == 0) { |